Method of making perforated concrete pipes



Dec. 5, 1939. J. ARBORIO METHOD OF MAKING PERFORATED CONCRETE PIPES Filed Aug. 25, 1957 Patented Dec. 5, 1939 UNITED STATES *ATENT creme METHO-ll) OF MAKING PERFORA-TED CONCRETE PIPES 6 Claims.

This invention relates to concrete pipes and method of making the same, and more particularly to a concrete pipe provided with perforations over a part of the circumference thereof, so that drainage water may enter the pipe from theupper side when the latter is laid horizontally,"

Recently the making of concrete pipe has become of considerable importance in that many 'sizes'and varieties of pipe are made of this material'which were formerly made of tile. If handled correctly and if the proper methods are employed, concrete lends itself quite admirably to the making of pipes, as it can be poured or packed 15 into forms of the desired shape, so that a pipe of the desired size and wall thickness will be obtained.

In the method herein described, a form is used for the exterior surface of the pipe. None, however, is employed for the interior. Instead a plunger or ram, having on its end what may be termed a packer head, is rotated within the pipe as the concrete is being delivered therein, so that the latter will be packed tightly against the wall of the form, and thus provide the interior opening. Moreover, in order to make a pipe having perforations or openings in the wall thereof, it is necessary to provide for such openings when the concrete is being packed. In order to do this, I

pack the concrete about pins which project into the-form, the inner ends of the pins, however, being just short of the inner surface of the pipe wall, so that there will be no danger of these pins interfering with the packer head. The concrete isformed about the pins, so that when the'pins are removed from the pipe, perforations exist from the outer wall to a point within a very short distance of the inner wall. This small thickness of concrete or plug at the bottom of the hole may be easily punched out before the concrete has become fully set, so that clean-cut perforations formed entirely through the wall will be provided.

One object. of the invention is to provide a novel and improvedmethod of making concrete pipe.

Another. object of the invention is to provide an improved method of making a concrete pipe having perforations in a portion of the wall 50X thereof, the perforations preferably extending substantially throughout the-longitudinal dimension of thepipe, but being provided in only a port-ion of the pipe circumferentially.

A stillfurther object of the inventio-nis the provision ofa concrete pipe having drainage perforations formed in a portion only of the wall thereof.

To these andother ends the invention consists in the novel features and combinations of parts to-be hereinafter described and claimed. 5

In the drawing: v

Fig. I is-a longitudinal sectional view of apparatus used in connection with the practice of my improved process;

Fig. 2 isasectional View of the form. used for the concrete pipe; and

Fig; 3' is a sectional view on line 3-3 of Fig. 1.

Toillustrate-a preferred form of my invention, I have shown in the drawing certain apparatus for carrying out theprocess of making the concret-e pipe, It may be noted that a form is employed'substantially of theoutside dimensions of the pipe to bemade. The concrete is mixed and packedint'o this form by a suitable machine devised-forthis purpose. The concrete is in a very dry state, the expression very dry being relative; of course; a'sit is sufliciently moist to cause it to'set: It is hardl'ymore than moist, however, and not sufficiently wet so that His at all fluid.

In the making of 'the pipe I employ a form of generally cylindrical shape, such as shown at W in Fig. 1'. This form is placed over a support l i provided on a plunger l2, which support is movable in an opening in the floor or base I3. The support also carries a form block I l of cylindrical*shape, which is of smaller diameter and rests within the lower portion of the form ill.

The lower endof the form is flared, as shown at [-5, so that an annular space [6 remains betweentlie form and the block it to provide the end flange on the-finished pipe.

Secured to the upper and lower ends of the form. are lugs ii and I8 which are held in grooves i 9 and 2B, which grooves are provided in members 2-1 and 22-, secured respectively to the upper and lower supports I31 and 23'. This will prevent the form from turning during the rotation of the packer heao, as will be described hereinafter.

The upper supporting member 23 is provided I lines 28 in Figs. 1 and 2.

, dotted line 28 indicates the inner surface of the finished pipe, the wall of which, of course, lies between this line and the inner surface of the form [0.

As shown in Fig. 2, attached to frames 30, mounted upon the wall of the form, are pins 3| which are movably mounted in the frames 30 and adapted to project through openings 32 in the wall of the form. These pins are provided in longitudinal rows or gangs, six of such gangs be ing shown in connection with the form illustrat been rotated to a position to disengage these bars.

ed, as will be seen from inspection of Fig. 2 of the drawing. The pins of one row or gang are secured to a bar 33, so that, by moving the bar,- all of the pins of one gang may be moved in and out simultaneously to withdraw them from a protracted position within the form, and so withdraw them from the pipe after it has been packed when it is desired to remove the form. A retaining member 34 is rotatably mounted on a pin or bolt 35 attached to the form between two adjacent bars 33, the member 34 being rotatable into the position shown in Fig. 2 to engage the bars, and hold the pins in protracted position, as shown inFig. 2, by reason of the action of the compression spring 36, which bears against the nut 31 on the bolt 35 at one end, and at its other end upon the retaining member 34. The pins are thus resiliently held in protracted position, but may be retracted from the form when the retaining member is rotated through an angle of from the position shown in Fig. 2, so that it will clear the bars 33 and permit the bars to be drawn outwardly and the pins retracted. The form I!) is separable into two longitudinal sections or halves, as shown at 38 and 39, the two halves being held together by the clamps 40 and 4|. The structure of this form is described more particularly in my co-pending application, Serial No. 155,877, so that further description herein will be unnecessary,

In the making of concrete pipes according to the present method, the form I0 is placed with its axis in a vertical position on the table H and centered over the form block 14, where it is secured in place by means of the lugs l1 and 18, which are positioned in grooves I9 and 20 in members attached to the upper and lower supports. The pins 31 are moved inwardly and secured in this protracted position by theretaining members 34, which are moved to the positions shown in Fig. 2. The plunger 25 carrying the packer head 26 is advanced downwardly into the form until the packer head contacts with the block- M.

The mix is then poured into the form at the proper rate, and at the same time the packer head 26 is rotated and gradually withdrawn from the form in an upward direction. The concrete mix is relatively dry, as hereinbefore stated, but contains sufficient moisture so that it will properly set. The blades 2'! upon the packer head throw the concreteoutwardly against the wall of the form sothat it is packed tightly against this wall, the mix being fed in at the proper rate to fill the space between the packer head 26 and the wall of the form. When the packer head has been withdrawn from the form, the space outside of the dottedline 28 will have been completely filled with firmly packed concrete, and the space within this line left by the removal of the packer head will, of course, be the opening through the pipe. It will be noted that the pins extend inwardly to a point just short of the dotted line 28, so that the openings formed in the wall of the pipe by these pins do not extend quite through the wall.

When the form has been filled, as described, it is released from the machine and carried by a suitable truck to a place where the concrete may be allowed to set. The clamps 40 and M are loosened, the pins 3! are withdrawn from the interior of the form, and the parts of the latter are at once removed from the pipe. The withdrawal of the pins 3! is effected by drawing outwardly the bars 33 after the retaining members 34 have The two halves of the form may then be freely removed. It will be understood that the concrete has not yet set, but as it is in a comparatively dry state, and as it has been packed tightly against the'wall of the form, it will be self-sustaining untilthe setting has been completed. The small amount of material left at the inner ends of the openings formed by the pins 3| may be knocked out with a punch or similar tool so as to complete these openings through the wall of the pipe.

While I have shown and described a preferred embodiment of my invention and a preferred method of carrying out my improved process, it is to be understood that the invention is not to be limited to all the details shown, but is capable of modification and variation within the spirit of the invention and within the scope of the ap pended claims.

What I claim is: l. The method of making a perforated concrete pipe which comprises inserting pins through the openings in the wall of a hollow form having the internal shape desired for the external form of the pipe, packing the concrete mix against the wall of the form and around the pins while leaving an opening along the axis of the form, yieldingly holding said pins against outward movement during the paoking operation, withdrawing the pins from the interior of the form, and then removing the form from the pipe so formed.

2.'The method of making a perforated concrete pipe which comprises inserting pins through the openings in the wall of a hollow form having the internal shape desired for the external form of the pipe, packing the concrete mix against the wall of the form and around the pins while leaving an opening along the axis of the form, yieldingly holding said pins against outward movement during the packing operation, withdrawing the pins from the interiorof the form, and then removing the form from the pipe so formed prior to the setting of the mix. g I 3. The method of making a perforated concrete pipe which comprises inserting pins throughthe openings of a hollow form having the internal shape desired for the external form of the pipe, packing the mix tightly against the wall of the form around said pins from the bottom of the form progressively upwardly vwhile leaving. an opening along the axis of theform, yieldingly holding said pins against outward movement dur ing the packing operation, withdrawing thepins from the interior of the form, and then removing the form from the finished pipe. g,

4. The method of making a perforated concretepipe which comprises inserting pins through the opening of a hollow form having the internal shape desired for the external form of the pipe, pouring a concrete mix into the upperend of the form when the latter is in a vertical position, promovement during the packing operation, then,

jecting a tool into said form from the upper end thereof, and rotating said tool during the feeding of the mix to the form to pack the mix against the wall of the'form and around said 'pins and leave an opening along the axis of the form, yieldingly holding said pins against outward Withdrawing the pins from the interior of the form, and removing the form from the finished pipe.

5. The method of making a perforated concrete pipe which comprises inserting pins through the opening of a hollow form having the internal shape desired for the external form of the pipe, introducing into the upper end of the form while the latter is in a vertical position a rotating tool spaced slightly from the inner ends of said pins, introducing a relatively dry concrete mix into said form from the upper end thereof, and rotating and gradually withdrawing said tool during the introduction of the mix to pack the latter against the wall of the form and around the pins and leave an opening through the center of the form pipe, yieldingly holding said pinsagainst outward movement during the packing operation, and thenwithdrawing the pins from the interior of the form, and removing the form from the plpe.

6. The method of making a perforated concrete pipe which comprises inserting pins through the opening of a hollow form having the internal shape desired for the external form of the pipe, introducing into the upper end of the form while the latter is in a vertical position arotating tool spaced slightly from the inner ends of said pins, introducing a relatively dry concrete mix into said'form from the upper end thereof, rotating and gradually withdrawing said tool during the introduction of the mix to pack the latter against the wall of the form and around the pins and leave an opening through the center of the form pipe, then withdrawing the pins from the interior of the form, removing the form from the pipe, and thereafter punching out the bottoms of pins.

' JOHN ARBORIO. 

